The invention relates to a device for closing and opening mold halves of at least one mold of glass forming machine.
In the case of a known device of this type (U.S. Pat. No. 1,911,119A, FIGS. 3 and 8, or DE 20 27 243 B2, FIG. 3), the devices for closing and opening the blank mold halves and finishing mold halves are formed in a similar manner. In each case, the two intermediate members are driven in a reciprocating manner by means of a piston rod of a piston-cylinder unit. The two piston-cylinder units are disposed in the interior of the frame (box) of the I.S. (individual section) glass forming machine. In this manner, the two piston-cylinder units take up a lot of useful space inside the frame. Moreover, the linear movement of each piston rod is no longer sufficiently precise and suitably reproducible to meet the current requirements for the production of hollow glass.
A parallel closing device for mold halves is known per se from DE 198 51 133 A1. A servo motor is arranged with a vertical longitudinal axis and drives a lead screw by means of its upper driven shaft via a coupling, which lead screw comprises lower left-hand threads and upper right-hand threads. In each case a leftward nut and a rightward nut are in engagement with these opposed threads. The nuts are each connected via an articulated lever pair to a common horizontal pivot shaft. The pivot shaft together with the mold half support mechanisms is moved in a reciprocating manner in a horizontal plane upon rotation of the lead screw. FIG. 3 illustrates the closed mold position, whereas FIG. 4 shows the open mold position. This design is comparatively costly and requires a relatively large amount of space both in the horizontal and vertical direction.
From DE 299 16216 U1 of the Applicant it is known perse to drive a worm rotationally in a reciprocating manner by means of a drive. At diametrically opposed positions, gear wheels are in engagement with the worm. Each gear wheel is affixed to a shaft which supports a crank. Each crank is connected via a particular lever mechanism to a pivotal mold tool half holding mechanism.
From FIGS. 3 and 4 of GB 2 331 096 A and FIGS. 3 and 4 of FR 2 782 509 A1 a device according to FIGS. 3 and 4 of the previously discussed DE 198 51 133 A1 is known per se in each case.